If this is your first Amnesia mod (which judging by your post count and join date, it most definitely is) you should just do a regular old custom story. Full conversions are quite frankly overused, overrated and can cause damage to the Amnesia installations of people who play them. Even if you are meticulous and careful, you can still inadvertently damage a file -- and not even know how! I've done it before; I've seen other TC installations do it. For example, Insomnia's logo appears in the place of TDD's when you install and play it. My full conversion had a re-texture for a wall part which somehow ended up replacing the material for ropes. Don't ask me how -- I STILL have no idea.

If you are adamant on making a TC mod, there's plenty of documentation on it available for you to browse. Check the wiki, search the forums for they keyword "conversion" in thread titles, or visit tutorials elsewhere on the web.